I have a 1997 Jimmy. I smelled rubber burning, opened the hood and the idler pully is not turning. Is the idler pully just a pully, or does is it have another purpose?

Not good. Better have that car checked out asap by a qualified electrician since you have a nasty situation there. Smells like a massive short has invaded your car.

check for oil leaks around the engine manifold check rocker cover for leaks if its a diesel check the turbo charger for leaks check wiring around exhaust manifold

sound like AC COMPRESSOR clutch bearing going bad causing locking up putting drag on drive causing drive belt slip giving a burn rubber smell.

If you could be more specific on which pulley was sparking I could help more accurately

It sounds like the belt is slipping or maybe even the compressor is seized. Just check to see if the compressor is turning.

OK.
I would never remove an a/c belt in order to make a caravan run properly. The a/c compressor, when functioning helps to get rid of condensation on your windshield using the a/c compressor.

If you smell burning rubber this is not good.

Replace the a/c compressor which may cost a few hundred or so, but you'll have a/c and defrost working properly.

good luck on this one.

Sounds like your drive belt is slipping, it is either worn out or needs adjusting. You may near it louder when turn your steering wheel.

You may have a frozen bearing on the tensioner or belt idler. This will cause the belt to burn and smell. I think you are on the right track. I would remove the belt and spin the idler and adjuster by hand to see that they are free and don't have excessive play in them. Replace as necessary.

check the condition of the tensioner pully and the idler pully, make shoure they are turning freely, check for signs of belt draging

If its in the engine compartment there is an antifreeze leak..If it inside the car like like near to the windshield, you have a bad heater core. Good Luck contact me if you need more help.